Influence of temperature cycling and pore fluid on tensile strength of chalk

T. Voake*, A. Nermoen, C. Ravnås, R. I. Korsnes, I.L. Fabricius

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Calcite has a highly anisotropic thermal expansion coefficient, and repeated heating and cooling cycles can potentially destabilize chalks by breaking cement bonds between neighboring particles. Based on tensile strength measurements, we investigated how temperature cycles induce weakening of chalk. Tensile strength tests were performed on chalk specimens sampled from Kansas (USA) and Mons (Belgium), each with differing amounts of contact cement. Samples of the two chalk types were tested in dry and water-saturated states, and then exposed to 0, 15, and 30 temperature cycles in order to find out under what circumstances thermally induced tensile strength reduction occurs. The testing results show that the dry samples were not influenced by temperature cycling in either of the chalk types. However, in the water-saturated state, tensile strength is increasingly reduced with progressive numbers of temperature cycles for both chalk samples, especially for the more cemented Kansas chalk. The Kansas chalk demonstrated higher initial tensile strength compared to the less cemented Mons chalk, but the strength of both chalks was reduced by the same relative proportion when undergoing thermal cycles in the water-saturated state.
Original languageEnglish
JournalJournal of Rock Mechanics and Geotechnical Engineering
Volume11
Issue number2
Pages (from-to)277-288
ISSN1674-7755
DOIs
Publication statusPublished - 2019

Keywords

  • Anisotropic thermal expansion
  • Tensile strength
  • Weakening by heating and cooling cycles

Cite this

Voake, T. ; Nermoen, A. ; Ravnås, C. ; Korsnes, R. I. ; Fabricius, I.L. / Influence of temperature cycling and pore fluid on tensile strength of chalk. In: Journal of Rock Mechanics and Geotechnical Engineering. 2019 ; Vol. 11, No. 2. pp. 277-288.
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title = "Influence of temperature cycling and pore fluid on tensile strength of chalk",
abstract = "Calcite has a highly anisotropic thermal expansion coefficient, and repeated heating and cooling cycles can potentially destabilize chalks by breaking cement bonds between neighboring particles. Based on tensile strength measurements, we investigated how temperature cycles induce weakening of chalk. Tensile strength tests were performed on chalk specimens sampled from Kansas (USA) and Mons (Belgium), each with differing amounts of contact cement. Samples of the two chalk types were tested in dry and water-saturated states, and then exposed to 0, 15, and 30 temperature cycles in order to find out under what circumstances thermally induced tensile strength reduction occurs. The testing results show that the dry samples were not influenced by temperature cycling in either of the chalk types. However, in the water-saturated state, tensile strength is increasingly reduced with progressive numbers of temperature cycles for both chalk samples, especially for the more cemented Kansas chalk. The Kansas chalk demonstrated higher initial tensile strength compared to the less cemented Mons chalk, but the strength of both chalks was reduced by the same relative proportion when undergoing thermal cycles in the water-saturated state.",
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author = "T. Voake and A. Nermoen and C. Ravn{\aa}s and Korsnes, {R. I.} and I.L. Fabricius",
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Influence of temperature cycling and pore fluid on tensile strength of chalk. / Voake, T.; Nermoen, A.; Ravnås, C.; Korsnes, R. I.; Fabricius, I.L.

In: Journal of Rock Mechanics and Geotechnical Engineering, Vol. 11, No. 2, 2019, p. 277-288.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Influence of temperature cycling and pore fluid on tensile strength of chalk

AU - Voake, T.

AU - Nermoen, A.

AU - Ravnås, C.

AU - Korsnes, R. I.

AU - Fabricius, I.L.

PY - 2019

Y1 - 2019

N2 - Calcite has a highly anisotropic thermal expansion coefficient, and repeated heating and cooling cycles can potentially destabilize chalks by breaking cement bonds between neighboring particles. Based on tensile strength measurements, we investigated how temperature cycles induce weakening of chalk. Tensile strength tests were performed on chalk specimens sampled from Kansas (USA) and Mons (Belgium), each with differing amounts of contact cement. Samples of the two chalk types were tested in dry and water-saturated states, and then exposed to 0, 15, and 30 temperature cycles in order to find out under what circumstances thermally induced tensile strength reduction occurs. The testing results show that the dry samples were not influenced by temperature cycling in either of the chalk types. However, in the water-saturated state, tensile strength is increasingly reduced with progressive numbers of temperature cycles for both chalk samples, especially for the more cemented Kansas chalk. The Kansas chalk demonstrated higher initial tensile strength compared to the less cemented Mons chalk, but the strength of both chalks was reduced by the same relative proportion when undergoing thermal cycles in the water-saturated state.

AB - Calcite has a highly anisotropic thermal expansion coefficient, and repeated heating and cooling cycles can potentially destabilize chalks by breaking cement bonds between neighboring particles. Based on tensile strength measurements, we investigated how temperature cycles induce weakening of chalk. Tensile strength tests were performed on chalk specimens sampled from Kansas (USA) and Mons (Belgium), each with differing amounts of contact cement. Samples of the two chalk types were tested in dry and water-saturated states, and then exposed to 0, 15, and 30 temperature cycles in order to find out under what circumstances thermally induced tensile strength reduction occurs. The testing results show that the dry samples were not influenced by temperature cycling in either of the chalk types. However, in the water-saturated state, tensile strength is increasingly reduced with progressive numbers of temperature cycles for both chalk samples, especially for the more cemented Kansas chalk. The Kansas chalk demonstrated higher initial tensile strength compared to the less cemented Mons chalk, but the strength of both chalks was reduced by the same relative proportion when undergoing thermal cycles in the water-saturated state.

KW - Anisotropic thermal expansion

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KW - Weakening by heating and cooling cycles

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